This study employs the technique developed in the earlier studies of the authors aimed atcomplex permittivity reconstruction of layered materials in the form of diaphragms (sections) in a single-mode waveguide of rectangular cross section from the transmission coefficient measured at different frequencies. The permittivity is assumed to be a function of frequency. We develop a numerical-analytical method of solution to this problem which guarantees accuracy of the result and can be easily implemented in view of practical measurements.Numerical results are presented for different types of materials.